Answer:
Your answer would be D.
They are defined by their different physical features.
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Answer:
The alveolar walls and capillary walls share a membrane. That's how close they're getting. This allows oxygen and carbon dioxide to readily pass from the respiratory system to the circulation. Oxygen molecules bind to red blood cells as they return to the heart.
Answer:
Night or Day
Explanation:
when the earth is tilted towards the sun it is day and when it's titled away it is night
C. Combine with hemoglobin to form oxyhemoglobin
It would be the 3rd option: Reaction to a stimulus helps maintain homeostasis.
Do you need an explanation?